The present invention relates to a method of controlling the gear changing operation in an automatic transmission in accordance with a determination of an optimum gear position based on a vehicle speed and a depth to which an accelerator pedal has been depressed, and more particularly to a method of controlling gear the changing operation during deceleration of the vehicle while the accelerator pedal is released.
There has been proposed, in the recent past, an automatic transmission for effecting the gear changing operation of a gear transmission having gears on parallel shafts with a gear changing actuator controlled by an electronic control device. The proposed automatic transmission has a synchromesh system for forward gear positions. The synchromesh system produces a gear shift sound or click when two rotating bodies or cones turning at different speeds are brought into synchronism in a short period of time so that any relative cone speed difference will be eliminated. The automatic transmission also generates sounds during a gear changing operation when shift forks in the gear change actuator and the transmission hit stoppers. These mechanically induced sounds do not normally attract driver's attention during driving operation, particularly when the driver is travelling normally. However, while the car is being decelerated with the accelerator pedal released, for example, from the speed of 70 km/h to a stop, the transmission gears are shifted down successively from the 5th to 4th to 3rd to 2nd to 1st gear position. When the car is braked until it is stopped, even though the clutch is not connected the gear changing actuator operates to shift the gears from the 4th to 3rd to 2nd gear position. Therefore, the gear change actuator is unnecessarily operated to produce successive noisy shift sounds which makes the driver uncomfortable.